Ethnic Disparities Found in A1c Test
A new study released by the Children's Hospital of New Orleans has found that black children with type 1 diabetes scored higher on A1c tests than white children who had similar blood glucose levels. Such ethnic disparity has already been shown in previous studies with adults.
The six-year study was led by Dr. Stuart A. Chalew, a professor of pediatrics at Louisiana State University Health Sciences Center. It tracked 276 children who averaged 12.5 years of age and had had type 1 diabetes for an average of about 5 years. The researchers looked at results of the A1c screening test, which is an indicator of blood sugar levels over the previous two to three months.
In the normal 120-day life span of the red blood cell, glucose molecules react with hemoglobin, forming glycated hemoglobin. Individuals with poorly controlled diabetes accumulate much more glycated hemoglobin than healthy people, which is reflected by higher A1c scores. Measuring glycated hemoglobin with the A1c test on a regular basis assesses the effectiveness of therapy by monitoring long-term serum glucose regulation. The study also tracked blood sugar levels from glucose tests that the participants gave themselves for at least a month.
The result of the study is that black children had statistically significantly higher A1c scores (9.1% ± 0.1) than white children (8.3% ± 0.1), independent of covariates. Results were controlled for age, diabetes duration, and mean blood glucose levels.
The 2010 American Diabetes Association Standards of Medical Care in Diabetes has set an A1c higher than 6.5% as a criterion for the diagnosis of diabetes. Higher A1c's, which correspond with poorer glucose control, are handled with treatment options to bring a patient within the A1c guidelines, including treatment with insulin as well as lifestyle changes. The intensity of treatment is determined by how far off the guidelines the patient is.
If the higher A1c levels found in black children are a factor of ethnicity, not actual elevated levels of blood glucose, they could have a potentially dangerous effect when treating diabetes based upon A1c.
If these tests come back too high simply due to ethnic disparity, the intensive glycemic control required to reach an ostensibly healthy level could "unintentionally provoke increased episodes of life-threatening hypoglycemia [low blood sugar] in African-American patients," Dr. Chalew said. Thus, practitioners need to consider each individual patient's health, biological background, risk of hypoglycemia, and specific health risks when setting a target A1c level and determining treatment.
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